Cell-Morphology Profiling of a Natural Product Library Identifies Bisebromoamide and Miuraenamide A as Actin Filament Stabilizers

Natural products provide a rich source of biological tools, but elucidating their molecular targets remains challenging. Here we report a cell morphological profiling of a natural product library, which permitted the identification of bisebromoamide and miuraenamide A as actin filament stabilizers. Automated high-content image analysis showed that these two structurally distinct marine natural products induce morphological changes in HeLa cells similar to those induced by known actin-stabilizing compounds. Bisebromoamide and miuraenamide A stabilized actin filaments in vitro, and fluorescein-conjugated bisebromoamide localized specifically to actin filaments in cells. Cell morphological profiling was also used to identify actin-stabilizing or -destabilizing natural products from marine sponge extracts, leading to the isolation of pectenotoxin-2 and lyngbyabellin C. Overall, the results demonstrate that high-content imaging of nuclei and cell shapes offers a sensitive and convenient method for detecting and isolating molecules that target actin.